I went in skeptical and bought Tier 3, and honestly my experience exceeded what I expected. The platform has a learning curve, support runs through email, but the onboarding walked me through enough that I was running my first campaign the same week.
In my case, 2,271 credits got me 311 items, and once I understood that credits are charged per result pulled, the math tracked with how it was presented on AppSumo. Setting my filters tighter cut down the generic and empty contacts a lot, so my second campaign was noticeably more efficient.
I also spot-checked the metrics myself against MOZ before trusting them, and they lined up close enough that I'm comfortable using the data to evaluate sites for link building and guest posting.
One thing worth knowing going in is that organic traffic metrics need your own Ahrefs API or subscription. I already had Ahrefs, so for me it was a non-issue, and I'd rather plug in my own source than pay a markup for someone else's.
What stood out most was the response when I raised questions. I emailed about my credit usage and got a real answer explaining where the spend went, plus a couple of specific filter changes to try. It didn't feel like a canned reply, and the suggestions actually worked.
If you plan to use this mainly for link building or guest posting, go in expecting to learn the tool and bring your own Ahrefs, and it earns its keep. For me the value clearly justified the cost.